Systems for accessing a data base over telephone lines and displaying the received information on a television set are well known. A disadvantage of such systems, however, is the fact that a computer keyboard is needed at each user location to format the communication from the user to the data base into a digital code such as ASCII which the data base can understand when it is transmitted over the telephone line.
A communication system of this prior art type requires two bidirectional modems (modulator-demodulator combinations) to translate the digital code into a frequency-shift keyed tone sequence transmitted over the telephone line, and back into digital code again at the other end. Modems and keyboards are relatively expensive and, if not well built, may present maintenance problems in a home environment. As a result, marginal users of a data service are deterred from subscribing to the service.